Hi Scord. I just sent you a note a moment ago.
You will find that these topics require time to experience what works and what doesn't. The gas problem was there before your surgery but you were better able to deal with it. I'm 20+ years with my colostomy and I'm still getting up through the night.
I've had bad experiences with "vents" in the appliances. I started with Convatec and I'm now with Hollister. A couple of months ago, the Hollister ET sent me samples of their latest filtered vent appliance but it was so well filtered that it simply didn't release the gas. I still had to "burp" the appliance. The earlier versions would actually soak up the waste in the pouch and pretty soon I'd notice a smell around me.
Get some free samples from your supplier in order to gauge your own experience.
Also, the later you eat at night, the more likely you'll be dealing with output in bed, so, a few comments: avoid large meals, late in the evening; avoid/minimize rich foods (which probably gave you grief before the surgery); chew everything VERY well (my first post-op experience with mushrooms made for a very interesting viewing in a public washroom).
Popcorn is very difficult for ostomates as it causes blockages. When you experience your first blockage, you will remember it for some time. So, I strongly suggest you avoid the foods which you know will block your system. If you feel the need, small amounts ...